We often hear it said that it's high in oxalates. This is not true, kale is actually a good , healthy addition to a beardie's diet. Here's a link to a study done recently :
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0ahUKEwjm24Cih8HYAhWJKyYKHZl2BigQFggsMAE&url=http%3A%2F%2Fnews.medill.northwestern.edu%2Fchicago%2Fkale-sheds-bum-rap-on-kidney-stones%2F&usg=AOvVaw2o3jzfy8zjKaGQLVpUqZeP
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=0ahUKEwjm24Cih8HYAhWJKyYKHZl2BigQFggsMAE&url=http%3A%2F%2Fnews.medill.northwestern.edu%2Fchicago%2Fkale-sheds-bum-rap-on-kidney-stones%2F&usg=AOvVaw2o3jzfy8zjKaGQLVpUqZeP